


Experimenter Bias

by longleggedgit



Category: Tennis no Oujisama | Prince of Tennis
Genre: M/M
Language: English
Status: Completed
Published: 2014-01-19
Updated: 2014-01-19
Packaged: 2018-01-09 06:33:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,180
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1142660
Author URL: https://archiveofourown.org/users/longleggedgit/pseuds/longleggedgit
Summary: <blockquote class="userstuff">
              <p>Inui learns what a fine line it is between research and field study.</p>
            </blockquote>





	Experimenter Bias

**Author's Note:**

> This fic was written for [](http://nerfracket.livejournal.com/profile)[**nerfracket**](http://nerfracket.livejournal.com/) for [](http://triopuri.livejournal.com/profile)[**triopuri**](http://triopuri.livejournal.com/) 2008\. Thanks so much to my betas, [](http://crocoduck.livejournal.com/profile)[**crocoduck**](http://crocoduck.livejournal.com/), [](http://cmere.livejournal.com/profile)[**cmere**](http://cmere.livejournal.com/), and [](http://anjenue.livejournal.com/profile)[](http://anjenue.livejournal.com/)**anjenue**. ♥

It started getting more difficult to collect data on Tezuka as soon as Echizen came into the picture, which annoyed Inui until he realized Echizen made collecting Tezuka's data even more interesting. With Echizen, Inui had an entirely new test group to document, and provided he could actually get close enough to observe the two of them together, the reactions were delightfully volatile.

Getting close enough was the hard part.

"Echizen is down two games, but his form is considerably improved since their match four days ago," Inui murmured into his digital recorder. In response, it began to vibrate to the thankfully subdued tune of _Toxic_.

Inui frowned and flicked a button on the side to silence it. For the first time, he was grateful that his hiding place behind a conveniently planted bush was a good few meters from the tennis court. It was still a mystery why he'd let Renji talk him into buying a two-in-one digital audio recorder/MP3 player, much less one made by an American company that seemed entirely too prone to malfunctioning. He would have to take it apart again when he got home.

"Tezuka appears to be perspiring at least 27% more than usual," Inui continued, pausing to scribble out a few hasty equations. He'd had to devote an entire notebook to Tezuka and Ryoma together when trying to jump between one for each of them had become too troublesome. "Likelihood of perspiration being due to physical stimulus alone: 14%."

Inui frowned again and slipped his pen back into his pocket. In note-taking, he'd missed another point taken by Tezuka. He was startled to realize it was already the end of the match.

"Game set won by Tezuka," Inui said into the recorder. It beeped and he gave it a frustrated smack.

"Echizen," Tezuka said, stepping up to the net. Echizen sidled forward as well, still out of breath and gripping his racket until his knuckles went white.

"Buchou," Echizen said in reply. He cocked his head to meet Tezuka's eyes arrogantly. Neither of them moved. Inui lifted an eyebrow.

 _They're doing it again,_ he scrawled quickly.

"You're improving," Tezuka said.

"Of course." Echizen tossed his hair out of his face and gave a smirk that managed to appear cocky and frustrated at once. He continued to watch Tezuka's face. Tezuka continued to watch back.

"Eye contact maintained for fourteen seconds," Inui said into his recorder. "Sixteen . . . seventeen. . . ."

The recorder beeped loudly. Inui looked down in distress.

"Buchou," Echizen repeated, voice serious and challenging, and Inui felt his thumb hit the wrong button even as his head swiveled up to get a better look.

The recorder exploded with music, a female voice singing something about her London Bridge in English, and Inui cringed, fumbling to switch it off. For a moment, everything was blissfully silent. It didn't last long.

"Inui," Tezuka said after a pause. "Come out of the bushes."

Inui stood up awkwardly, sticking the recorder in his back pocket. "Hello, Tezuka." He picked a leaf out of his hair and smiled. "Echizen."

Echizen frowned and tugged at the brim of his hat. "What are you doing here, Senpai?" he asked.

"Nothing of great importance," Inui said with a dismissive wave of his hand. "I was merely asked to assist the, ah, Botany Club in identifying the different varieties of shrubbery on campus –"

"Inui," Tezuka said sharply.

Inui cleared his throat. "I was collecting data," he admitted.

Tezuka crossed his arms in front of his chest in the way he only did when he was entirely unimpressed, and Echizen let out a faint "che."

"You can collect tennis data at practice, Inui," Tezuka said.

"But I wasn't collecting data on your tennis," Inui said before he could stop himself.

Tezuka didn't immediately reply. He seemed at a loss for words, although Inui couldn't be sure – he'd only confidently documented Tezuka at a loss for words a handful of times before, and most of them were in direct correlation to Fuji. Echizen's face was mostly shadowed by his cap, but Inui almost thought he saw a hint of a smile there. His fingers itched to pick up his notebook.

"Explain," Tezuka said at last.

"Your relationship," Inui said without preamble. "It only depends on tennis to a certain point." Tezuka began to look a little ill, and Inui hurried to clarify, "You're not the only ones on the team whose personal lives I follow up on. Kikumaru and Oishi, for example –"

"What are you getting at, exactly?" Tezuka's cheeks had begun to color. Inui looked from Tezuka's flustered face to Echizen, who appeared mostly amused, and then back again.

"You can't – it's not possible you haven't realized," Inui stammered. "I was quite sure –"

"He knows about Oishi-senpai and Kikumaru-senpai," Echizen said helpfully. "We saw them in the clubhouse once."

Tezuka now looked both ill and dangerous, and he shot Echizen a warning glance before saying sternly, "This is just tennis, Inui."

Despite what he knew to be his better judgment, Inui laughed. "Tezuka," he said with a shake of his head. "It's never just tennis."

The silence was so thick Inui almost wished his audio recorder would turn back on. Tezuka stared for long enough that Inui felt the need to readjust his glasses, and then Tezuka turned away and picked up his bag without another word. Echizen didn't move, and Inui decided against it as well, despite further itching to grab his notebook. It wasn't until Tezuka was walking in the opposite direction across the tennis courts that Inui even remembered to breathe.

"Interesting," he murmured as he watched Tezuka's retreating form.

"Thanks, Senpai." Inui was surprised to note there wasn't a trace of sarcasm in Echizen's tone – he sounded genuinely grateful.

"Echizen?" Inui said.

"He needed a push." Echizen tipped his hat up and smirked, and Inui was left alone when he too scooped up his bag and headed across the tennis courts in the same direction as Tezuka, his pace marginally more brisk than usual.

"Very interesting," Inui said.

He fished his earbuds out of his back pocket along with the recorder and plugged them in, pausing to grab his notebook before heading back toward the school. This new data was going to require careful analysis and reconfiguration, of course, but for now, he wanted to finish that song.

***

The wisest course of action, Inui concluded after extensive deliberation, was to avoid Tezuka and Echizen as much as possible until a safe period of time had passed and they could all forget about the little spying episode. He made it two and a half days before he was crouching behind a different set of bushes near the tennis courts with a blank notebook and a brand new audio recorder in hand. One that didn't play MP3s.

"Point, Echizen," Inui said into his new recorder. He squinted and shifted slightly closer. "Correction. Point, Tezuka."

His current set of bushes was even further away than the old set, and Inui was beginning to wonder if trying to collect data from such a distance was even worth it. Considering that Tezuka had stopped to check the old set of bushes four times since their game began half an hour ago, however, Inui didn't see many alternative options.

"Buchou," Echizen called suddenly, and Tezuka stopped in the middle of a serve and lowered his racket. They both approached the net. Echizen appeared to be saying something, but Inui couldn't make it out. Tezuka frowned and carefully scanned their surroundings – for a brief, panicked moment, Inui could have sworn his gaze lingered on his new hideout – and then he turned to Echizen and said something back.

"They appear to be quarreling," Inui muttered as soon as he was confident he had not been spotted. Tezuka looked even more sullen than usual, and Echizen had none of his typical air of self-satisfaction. It was the first time Inui had ever seen either of them ignore a tennis ball for so long.

"Enough," Tezuka said, clearly and firmly. He made as if he was about to walk away, but Echizen grabbed his shirt and held him in place. Tezuka glared. Echizen glared back.

"Correction," Inui said, lifting both eyebrows. "They appear to be –"

Echizen jumped the net and fisted his hand in Tezuka's collar. In almost the same motion, Tezuka pushed him up against it and started kissing him.

Inui dropped his audio recorder, but neither Tezuka nor Echizen seemed to notice.

***

In the space of eight days, Inui documented Tezuka and Ryoma kissing seventeen times. They most commonly utilized the inside of the empty clubhouse, but he'd caught them at it on an abandoned tennis court twice more (Tezuka never let these excursions linger), once behind the outdoor sinks, and even once, in a hurried, guilty moment of carelessness, in the stairwell that led to the school basement. Tezuka kept his jacket on and his collar up at tennis practice to cover the faint red marks on his neck that Inui could just make out in science class. Echizen seemed determined to show his off, and smirked whenever Momoshiro threw a fit trying to figure out where they'd come from. The amount of time Tezuka and Echizen spent playing tennis when they were alone together began decreasing at an almost alarming rate, and Inui started jerking off more times in one day than he used to average in a week. Most days he didn't even make it home first.

In retrospect, Inui really should have predicted that this experiment was going to get him into trouble.

"Buchou," Echizen said, and Inui paused in pulling his jersey off to quickly analyze the meaning behind the tone of Echizen's voice, the exact time of day, Tezuka's reaction. There was a 90% likelihood they would be meeting in the clubhouse half an hour from the time practice ended. Inui pulled on his uniform and shut his locker.

"Have a good afternoon," he said with a smile and a nod to Tezuka.

Tezuka nodded in return and watched as Inui opened the door and stepped outside. He took an immediate left after disappearing from sight and walked around to the back of the clubhouse. When twenty minutes had passed, Inui jimmied the latch on the window with a pocketknife and climbed as silently as possible into the empty custodian's closet. He listened for any sound of movement outside the door, then replaced the screen and crept out of the closet, falling into a crouch behind a row of lockers where he had an unobstructed but well-hidden view of the bench Tezuka and Echizen typically occupied.

They hadn't even waited half an hour.

Echizen was straddling Tezuka's lap on the narrow bench and grinding his hips down with enthusiasm, his arms looped around Tezuka's neck and his mouth sucking a trail across his naked collarbone. Tezuka's shirt was in a wrinkled heap on the floor and his hands were fisted in the back of Echizen's.

"Echizen," he managed between gasps. "Not here."

Echizen paid his protests no more attention than usual. He leaned back to regard Tezuka steadily, then pulled his own shirt off and threw it aside. Tezuka took hold of Echizen's waist quickly enough that Inui guessed it was an involuntary reaction.

"Buchou," Echizen moaned, leaning in to mouth Tezuka's neck. Tezuka shuddered, then jumped halfway off the bench, which confused Inui until he realized Echizen's hand had snaked its way into Tezuka's shorts. The noises Tezuka started making were so out of character that Inui desperately wished his second audio recorder hadn't broken when he had dropped it outside. He'd already given the first one to Renji.

"Echizen," Tezuka said again, although whether in warning or encouragement, Inui couldn't tell. Echizen broke the kiss he had only just initiated, took one of Tezuka's hands from his hip, and guided it to the front of his own shorts. Inui and Tezuka both swallowed at the same time.

Echizen made a noise somewhere between a groan and a whimper and moved his hips to further encourage Tezuka's hand, halting his desperate motions and letting out a gasp when Tezuka finally dipped under Echizen's waistband and began to stroke. The sound of their mingled breathing was getting louder and more ragged, which was some small consolation to Inui, who was beginning to worry his own breathing would give him away.

No sooner had this thought crossed Inui's mind than Echizen tilted his head back and opened his eyes, looking directly at the corner locker Inui was hiding behind.

"Inui-senpai," Echizen said breathily. "Are you going to stop just watching already?"

Tezuka's head snapped up and Inui went momentarily paralyzed with shock, but Echizen just resumed sucking on Tezuka's neck and jerking him in his pants as if nothing out of the ordinary had occurred.

"Inui?" Tezuka said, his voice almost fearful.

Inui inhaled deeply and stepped to the side, bringing himself fully into Tezuka's view – and Echizen's, if he would care to stop devouring Tezuka for long enough to pay attention.

"Buchou," Echizen whined, pressing insistently against Tezuka's now-still hand. "Don't stop."

"Why –" Tezuka began, then his lips clamped shut and his face clouded over. "How did you know he was there?" he asked Echizen.

"He was completely obvious," Echizen said, sounding a little put-out to have been denied and pulling away just enough to speak clearly. "You've just been too distracted to notice."

"I'm sorry," Inui said before Tezuka could retort. "I'll go." His palms were sweating and he wiped them on his pants and turned toward the door, fighting to preserve what was left of his dignity and not bolt for it.

"You don't have to," Echizen said, and he seemed to surprise Tezuka as much as Inui when he added, "Right, Buchou?"

Inui froze in place and tried not to let the silence that followed make him completely lose his mind.

"I shouldn't have interfered," Inui said when waiting became too much. "It was –"

"Don't," Echizen interrupted. Inui turned back and Echizen and Tezuka were locked, watching each other eye-to-eye. For a few seconds that felt infinitely longer, no one spoke or moved. Then Tezuka finally, very carefully, nodded.

Echizen smiled. "Come here, Senpai," he said. Inui was startled by the speed with which he obeyed.

"I –" he started again, situating himself on the bench with his chest pressed to Echizen's back.

"You're noisy," Echizen said. He pulled his hand out of Tezuka's shorts – Inui was only now dizzily realizing it had been in there the entire time – and took hold of Inui's collar, tugging him forward until he was leaning over Echizen's shoulder, face-to-face with Tezuka.

Inui's breath caught and he considered pulling away, but something in Tezuka's eyes kept him grounded where he was. He opened his mouth, maybe intending to apologize again, but before he could pause to work out the pros and cons of this strategy he was clutching the back of Tezuka's neck with one hand and Echizen's shoulder with the other, forcing his and Tezuka's lips violently together. There was hesitation at first, which was only to be expected, but Inui was both surprised and thrilled to find Tezuka soon returning the kiss with at least as much enthusiasm.

Echizen hummed in approval. "Buchou liked you first," he said. Inui broke the kiss, startled, and noticed Echizen was watching them both in smug satisfaction. "Right, Buchou?"

Tezuka flushed and didn't say anything, and Inui wondered how he could have possibly overlooked this piece of data.

"Oh," Inui said. He pushed his glasses up on the bridge of his nose, took hold of Tezuka's neck again, and kissed him even harder.

"Senpai," Echizen said impatiently, making it clear he was addressing the both of them. Tezuka broke the kiss this time and they both looked down at Echizen, who was using Inui's body for support as he slipped out of his shorts and underwear completely. Inui continued to stare but Tezuka looked aside, blushing furiously.

"You need to catch up," Echizen said, glancing over his shoulder at Inui, and Tezuka was forced to tear his attention away from the floor when Echizen slid forward and climbed naked into his lap.

Inui shrugged out of his shirt without waiting for further incentive and remained focused intently on the spectacle before him, shivering slightly when Tezuka's resolve almost visibly snapped and he tangled a hand in Echizen's hair to allow a better angle for attacking the side of his neck. Echizen squirmed and hissed and curled his fingers around Tezuka's shoulders.

"Inui-senpai," Echizen said breathily, not bothering to open his eyes. He hooked one finger in the waistband of Tezuka's shorts and tugged. "Help Buchou."

He only waited long enough for Tezuka to give him an embarrassed, assenting nod. Echizen slipped out of Tezuka's lap and in a moment Inui was on his feet and pulling Tezuka to his, guiding him by his hips until his back collided sharply with a locker door. Tezuka's eyes widened in surprise but he made no protest, and when Inui nuzzled the side of his jaw and began to drag his tongue from the place just below his ear all the way down to his collarbone, he could almost feel Tezuka's knees buckle.

"You always appreciate when Echizen does that," Inui said hotly against Tezuka's skin.

"He appreciates when you do it, too," Echizen said from the bench.

Inui chuckled and Tezuka tensed as he bent lower and began to bite and suck his way across Tezuka's chest, working down to his navel and dropping to his knees. With one efficient tug, Tezuka's shorts and underwear were in a pool around his ankles. He could hear Echizen's quick inhale almost more clearly than he saw Tezuka's hips buck forward, the way his whole body seemed to be trembling.

"Inui," Tezuka said, and Inui suspected it was meant to sound admonishing, but the way Tezuka's hand moved down to run through the hair on the back of Inui's neck was anything but. Inui stood up again, trailing fingers from the line of Tezuka's hip to the base of his cock, watching Tezuka's features dance between reluctance and want.

"Stay still," Inui said, leaning in almost as if to kiss him but bringing his lips next to Tezuka's ear instead. He wrapped his fingers around Tezuka's cock, felt it harden in his grip, and began to stroke, slow and painstaking. It was easy, judging the appropriate pace for Tezuka as opposed to Echizen. Echizen's every movement suggested a certain unrestrained neediness, a desire to be done to instead of to do for. Echizen was used to getting his way, and fast. With Tezuka, simply breathing against his skin could be enough. Not that Inui had any plans to stop there.

From behind them, Inui heard Echizen's breathing pick up, and judging by the way Tezuka's expression went suddenly from heavy-lidded to stunned, there was little mystery as to what he was doing.

"Keep watching," Inui ordered. Tezuka's eyelids fluttered, but Inui knew that he would be incapable of disobeying even if he wanted to. He watched Tezuka watch Echizen and quickened the pace of his hand, reveling in the way a flick of his wrist or drag of his fingernail could make Tezuka gasp and shudder. On the bench, Echizen moaned out loud, and Tezuka became so overwhelmed he had to grab onto Inui's neck to steady himself. Inui sucked Tezuka's earlobe into his mouth, bit down gently, and began counting down in his head. Tezuka came on one.

Inui paused to wipe his hand on his pants and, despite being quite positive Tezuka would need a short recovery period, was pleasantly surprised as Tezuka dropped his hands to Inui's pants and began to unbutton them, at the same time kissing his face and neck and urging him backwards toward the bench. The backs of Inui's legs bumped into Echizen's knees and he allowed himself to be undressed from in front and behind, meeting Tezuka's kisses occasionally, letting out a little groan when Echizen's fingernails raked across his ass and kicking his pants away as soon as they were at his feet.

Echizen was still hard and Inui exchanged a look with Tezuka before he dropped to straddle the bench and wrapped his arms around Echizen's waist, pressing close so his chest was again flush with Echizen's back. Tezuka dropped to straddle it in front, and Echizen drew him in closer even as he arched into the touch of Inui's tongue on his shoulder.

"Took you long enough," Echizen muttered cheekily.

"Tezuka," Inui said, before Tezuka could begin to get even redder. "He goes crazy when you suck on his collarbone."

Echizen sounded for a moment as if he was going to try and argue, but then Tezuka bent over and began to do just that, and Echizen could only curse and writhe and dig his nails into Inui's thighs. Inui smirked and took Echizen's cock deftly in hand.

"Call him Buchou," Inui murmured into Echizen's ear as he began to jerk him hard, fully aware Tezuka could hear every word. "He'll get better."

" _Buchou_ ," Echizen said in a way that managed to sound almost unbearably filthy, and Tezuka groaned into Echizen's skin and moved lower to suck on one of his nipples.

The task of moderating was so enjoyable that Inui had nearly forgotten about his own aching dick, and was entirely taken off-guard when Tezuka, without looking up from Echizen's chest, reached around and started to jerk Inui just as hard.

"Oh god," Inui choked. His grip on Echizen became erratic and he thrust forward against Tezuka's hand, gasping into Echizen's neck.

"Faster," Echizen whined, and Inui obeyed as best he could, biting down on the skin within his reach and speeding up both his wrist and his thrusts. Echizen whimpered and came, reminding Inui he'd forgotten to count down this time. He couldn't really bring himself to lament, however – not when Echizen was pushing his hand away so he could turn around and reach in between Inui's legs himself, not when Echizen was smiling like he'd just won nationals and licking his lips teasingly before straining forward to lick Inui's.

"That was good, Senpai," Echizen said against Inui's mouth, only this time Inui couldn't quite figure out if it was intended for both of them or not.

He came twitching in Echizen and Tezuka's joint grasp, almost a full minute earlier than he typically took when he was alone, and despite wanting more than anything to watch as Echizen leaned back against Tezuka's chest, smug and sated and clearly ready for another kiss, his eyes closed of their own accord and stayed that way until his heart rate had slowed and his breathing was mostly under control.

When he opened them again, Echizen and Tezuka were no longer kissing, but they were watching him, Echizen smug, Tezuka perhaps a little flustered. There was probably some sort of protocol for following up situations like this with conversation, but Inui would be damned if he'd studied for it.

"The custodian will be here to collect the trash in fourteen minutes," he said helpfully. Tezuka blinked, and Echizen laughed.

"We'd better get showered, then," Echizen said. He made a show of wiping his hand on the side of the bench, then stood up, stretching lazily. Inui was glad to note that Tezuka was staring, too.

"Echizen," Inui said before he could completely turn the corner toward the shower room. "How long have you known I was watching?"

"The entire week," Echizen answered, rolling his eyes. "You need practice, Senpai."

Inui frowned but asked no further questions, and Echizen disappeared from sight. Tezuka cleared his throat, causing Inui to look up.

"I didn't know," Tezuka said.

Inui smiled. "Thank you, Tezuka."

Tezuka nodded once and stood up himself, despite the fact that it seemed to be taking all his will power not grab the nearest pair of dirty towels and cover up the both of them.

"We should shower as well," Inui said, jumping to his feet and throwing Tezuka a grin that didn't seem to reassure him at all. Without hesitation, Inui leaned over and slapped Tezuka soundly on the ass. Tezuka's face drained of all color, and Inui's grin faded away.

"Inui," he said. "If you ever do something like that again, you're going to be running laps until you graduate."

"Sorry, Buchou," Inui said. Tezuka turned without another word and followed after Echizen, but Inui didn't miss the fact that his walk was decidedly stiff and the back of his neck a little red.

"Interesting," Inui muttered.

Before he could follow suit, he stopped at his locker and pulled out his notebook, taking just a moment to scribble another detail on _buchou_ before slipping it back in its place. He smiled to himself and began to hum as he headed toward the shower room. It was reassuring to know there was still plenty of data that needed collecting.

_end_  



End file.
